Demand for cellular data capacity has grown exponentially. In order to meet this growth, interest has turned to cellular systems having large antenna arrays that are referred to as Massive multiple-input and multiple-output (Massive MIMO) or Full Dimension MIMO (FD-MIMO). Such large antenna arrays are capable of achieving higher spectral efficiencies by serving a greater number of users simultaneously. As a result, large antenna arrays are being considered as a promising new technology to deliver capacity enhancement in the future releases of 3GPP Long-Term Evolution (LTE) and LTE-Advanced (LTE-A) cellular systems.
Interference is a major source of performance degradation in cellular systems. Massive MIMO using very large antenna arrays can substantially reduce interference and increase throughput. Higher number of antenna elements in a closely spaced antenna configuration enhances angular and spatial resolution by producing narrow and directive beams, thereby mitigating the interference. Coordinated Multi-Point (CoMP) is another technique to combat interference particularly for cell-edge cellular users wherein interfering transmitting points cooperate to boost average and cell-edge throughputs.
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